If he is that tight/predictable, is there any chance he folds his 55 for an all-in after the ace falls on the turn? I think you can be pretty sure it didn't help him. I forget stack sizes but I don't think he has odds to fill if he puts you on a straight.
What do you think about raising the flop to something like $40? This time you hit your out but in most cases I think you are gonna lose more if you stick around and call off a bigger portion of your stack. When he raised to $18 you said you weren't sure whether he had a set or not so don't you think it's better to find out on the flop rather than later when it could get more expensive?